1. Field of the Invention
This application relates broadly to improved disposable medical pressure cuffs, particularly disposable, blood pressure measurement cuffs. It also concerns new methods for their production.
2. Description of the Prior Art
Flexible, inflatable pressure cuffs that can be wrapped about the arm or other body portion of a person or animal for measurement of blood pressure or as a tourniquet have been in existence for decades. Historically, such cuffs were of a permanent type that would be used by a physician or at a bed station in a hospital until they wore out and had to be replaced.
It has been long recognized that such cuffs constitute a potential source of cross-infection between patients. As a result, substantial work has been devoted to the development of structural arrangements and production methods seeking to provide medical pressure cuffs that are reliable for use in medical practice, but that can be made and sold at such a low a cost they can be treated as disposable items permitting them to be used on a single patient and then discarded, e.g., see U.S. Pat. Nos. 4,979,953; 5,101,830 and 5,193,549.
The earliest style of disposable pressure cuffs were formed from a single sheet of flexible, heat sealable plastic such as plasticized polyvinyl chloride or polyurethane with one or two small holes punched in a central area in which flanged inflation fittings are inserted and heat sealed by their flanges to the material. This sheet was then folded in half and its perimeter edges were sealed together with dielectric heat (RF heat sealing) to form the completed cuff. Small amounts of hook and loop fasteners are attached to the cuff by RF heat sealing or pressure sensitive adhesive so as to enable the cuff to be secured to a patient's limb.
This early style of disposable cuffs proved easy to manufacture, were reliable and offered the advantage of the plasticized material being easily cleaned. The plasticized material, however, proved to be uncomfortable to patients because of the clammy feeling presented by the plastic films in contact with the patients. Further, the plastic films on the patient's skin caused perspiration and provided a nutritive environment for bacteria growth. Accordingly, a second style of disposable cuffs was developed in which a non-clammy type fabric would contact the patient when the cuff was in the operative position.
Such second style cuffs are typically made in two different ways. In a first way, the cuff is formed by a single laminate sheet having an outside layer of soft fabric and an inside layer of plastic or elastomer (see U.S. Pat. No. 5,193,549) with one or two holes punched in a central area to which flanged inflation fittings are RF sealed. The sheet is then folded in half and its perimeter edges sealed together to form a completed cuff.
In a second way, the cuff is formed of one sheet of flexible plastic and a second separate, equal size piece of soft fabric with a plasticized backing, with the two sheets laid in contact with each other. One or two small inlet (inflation) tubes are laid side by side at one longitudinal edge and between the two sheets. A small, special RF die is used to seal the sheets about and around the inlet tubes and the cuff is then completed by RF sealing of the perimeter of the plastic and fabric sheets.
Both of the ways described above have advantages and disadvantages. In the first way, because the method of manufacturing allows flanged inflation fittings to be RF sealed, this results in leak free operation. The soft fabric materials that are used also provide the patient with increased comfort. However, such materials are much more expensive than plastic materials and are much more difficult to clean. The second way still provides the soft material next to the patient's skin, yet reduces material expense by using a plasticized material on the other side. However, this second way involves a disadvantage since the 360 degree seal around the inlet tubes is difficult to make so that there will be no leaks. Hence, most air leakage in disposable cuffs using this method occurs around the inlet tubes. The process also requires much more expensive equipment and sealing dies.